KR20060036081A - Scanning-based detection of ionizing radiation for tomosynthesis - Google Patents

Abstract

An apparatus for obtaining tomosynthesis data of an object (5) comprises a source (1) emitting radiation (2) centered around an axis of symmetry (3); a radiation detector (6) comprising a stack of line detectors (6a), each being directed towards the source at a respective angle (alpha1,.., alpha n,.., alphaN); and a device (7) for moving the source and the radiation detector relative the object linearly in a direction (8) orthogonal to the symmetry axis, while each of the line detectors is adapted to record line images of radiation as transmitted through the object in the respective angle.

Description

SCANNING-BASED DETECTION OF IONIZING RADIATION FOR TOMOSYNTHESIS

The present invention relates generally to a scanning based apparatus and method for obtaining tomosindisize data for object inspection.

X-ray medical diagnostics, such as mammography, are low dose methods that produce one or more images of a portion of a patient, such as the patient's chest, for example, to be examined to detect early stages of cancer.

Mammograms generally include obtaining two images of each of the patient's chests, one from the stomach and one from the flank. The doctor or radiologist then confirms the breast cancer by viewing images of the chest, ie mammograms.

While this is one of the best ways to detect early formation of breast cancer, there is still a possibility that detection of breast cancer will be failed by a doctor or radiographer who observes a mammogram. For example, breast cancer may be radiographically dense and may fail the test by being obscured by breast tissue with fibrous glands.

Tomosindisize images, in which a plurality of images are captured at different angles, are being studied to detect early formation of breast cancer. By combining the plurality of images, it is possible to reconstruct any plane in the chest imaged parallel to the detector. The more numbers of images are used, the better quality images are obtained in reconstructed tomosinic images.

In addition, various line detectors for detecting ionizing radiation are known in the art. Such a detector provides an instantaneous one-dimensional image, but the two-dimensional image can only be performed by scanning a line detector and optionally a radiation source in the direction across the one-dimensional detector array. Using such a detector in tomosincissa would be very time consuming because multiple images must be captured at different angles.

Therefore, it is a primary object of the present invention to provide a scanning based apparatus and method for obtaining toxin synthesized data of an object at a higher speed than can be obtained by using conventional scanning based apparatuses and methods.

In this regard, a particular object is to provide a scanning based apparatus and a scanning based method capable of instantaneously recording a plurality of one-dimensional images of an object by means of a plurality of one-dimensional detectors and by scanning a plurality of two-dimensional images of the object. Where one-dimensional images of each of the objects are recorded at different angles.

Another object of the present invention is to provide a scanning based apparatus and a scanning based method capable of recording a plurality of two-dimensional images of an object by scanning a plurality of one-dimensional detectors on the object, wherein each two-dimensional of each of the objects An image is recorded at different angles, and the number of two-dimensional images is greater than the number of one-dimensional detectors.

It is yet another object of the present invention to create a high quality two dimensional tomosinic-sized image with high spatial resolution, high signal-to-noise ratio, high dynamic range, high image clarity (contrast) and low noise from the covering tissue without being complicated. It is to provide a scanning based apparatus and a scanning based method.

It is yet another object of the present invention to provide a reliable, precise and inexpensive scanning based apparatus and a scanning based method.

In particular, these objects are achieved by the devices and methods as claimed in the appended claims.

The inventors have shown that divergent radiation sources that emit radiation concentrated around an axis of symmetry, and are directed towards the divergent radiation sources, respectively, so that the bundles of rays of radiation propagating at each of a plurality of different angles are transmitted to the object to be inspected. By providing a radiation detector comprising a group of line detectors that later enter the line detector, while recording the line image of the radiation as each line detector is transmitted through the object at each angle of different angles, By linearly moving the radiation source and the radiation detector in a direction perpendicular to the axis of symmetry, it has been found that a plurality of two-dimensional images can be formed, where each two-dimensional image is formed by only one of the line detectors. As recorded, multiple line images Is formed from.

Therefore, a plurality of two-dimensional images at different angles are generated in a single scan, which reduces the detection time by a factor corresponding to the number of generated two-dimensional images.

Preferably, one device is prepared for rotating the radiation detector about an axis of rotation perpendicular to the axis of symmetry, wherein the line detectors are each oriented towards the divergent radiation source after rotation, and another The light bundle of radiation propagating at each angle of the plurality of different angles is incident on the line detector such that the moving device is further arranged to repeat linear movement of the diverging radiation source and the radiation detector in relation to the object, Each line detector is adapted to record another plurality of line images of radiation as it is transmitted to the object at each angle of another plurality of different angles.

The data from the device is excellent for use in tomosincisize or laminographic imaging.

Line detectors are preferred, but not exclusively, to use gas based parallel plate detectors. Other line detectors that may be used include scintillator based arrays, CCD arrays, TFT and CMOS based detectors, liquid detectors and diode arrays, such as incident on the edge of an X-ray, near incident on the edge or Pin-diode arrays with normal incidence. The collimator structure can be arranged in front of the detectors to partially reject the scattered X rays.

Other features and advantages of the invention will be apparent from the following detailed description of the preferred embodiments of the invention, given below, which are given for purposes of illustration only and without limitation of the invention.

1 is a schematic illustration in plan view of an apparatus for acquiring toxin synthesized data for X-ray examination of an object in accordance with a preferred embodiment of the present invention;

2A-2C schematically illustrate, in plan view, each of the X-ray bundles as a particular X-ray bundle traverses an inspection object during a first scanning movement by the apparatus of FIG. 1;

3A-3C schematically illustrate in plan view, respectively, a particular X-ray bundle as a particular X-ray bundle traverses an inspection object during a second scanning movement by the apparatus of FIG. 1;

4 schematically illustrates a cross section of the line detector of FIG. 1 taken along line I-I.

The device of FIG. 1 is a divergent X-ray source 1, collimator 4, radiation detector 6 and X which produce an X-ray 2 concentrated around an axis of symmetry 3 (parallel to the z-axis). The ray source 1, the collimator 4, and the radiation detector 6 are firmly connected to each other so that the X-ray source 1, the collimator 4, and the radiation detector 6 Device 7 for scanning the object 5 to be inspected by linearly moving it in a direction 8 (typically parallel to the x-axis) perpendicular to the axis of symmetry 3.

₁, ...,

_n, ...

_N)들의 각각의 각도에서 전파하는 방사선(2)의 각각의 광선 번들(b₁, ..., b_n, ..., b_N)이 각각의 라인 검출기(6a)에 입사하게 한다. 라인 검출기(6a)들은 y 방향으로 확장하는 라인 이미지들을 기록하기 위해 y 방향으로 확장하고 있다.The radiation detector 6 comprises a group of line detectors 6a, each of which is directed towards the divergent radiation source 1, so that a plurality of different angles relative to the front of the radiation detector 6

₁ , ...,

_n , ...

_N radiation (2), each ray bundle (b _1, a _{..., b n, ..., b} N) in each angle of the propagating) should be incident on each of the line detectors (6a). The line detectors 6a extend in the y direction to record line images extending in the y direction.

The collimator 4 may be, for example, a thin film of tungsten material with narrow radiation passing slits formed by etching, the number of which corresponds to the number of line detectors 6a of the radiation detector 6. The slits are fitted to the line detectors 6a such that the X-rays passing through the slits of the collimator 4 are in the detector unit 6a, ie each of the light bundles b ₁ ,..., B _n ,. .., b _N ) will be reached. The optional collimator 4 prevents the radiation directed at the object 5 from being directed directly to the line detector 6a, thereby reducing the radiation dose to the object. This is useful for all applications where the object is a human or animal, or part thereof.

₁, ...,

_n, ...,

_N)들의 각각의 각도에서 대상물(5)에 투과되는 방사선의 복수의 라인 이미지를 기록한다.During scanning, the device 7 is exposed to the radiation source 1, collimator 4 and radiation detector associated with the object 5 in a linear manner parallel to the radiation detector in front of it, as indicated by the arrow 8. While moving (6), each line detector 6a has a different angle (

₁ , ...,

_n , ...,

Record a plurality of line images of radiation transmitted to the object 5 at each angle of _N ).

₁, ...,

_n, ...,

_N)들의 각각의 각도에서 대상물(5)에 투과됨에 따라 방사선의 이차원 이미지를 각각의 라인 검출기(6a)들이 얻을 수 있게 라인 검출기(6a)들의 각각이 전체 대상물을 가로질러 스캔될 수 있게 한다.Scanning of the object 5 is preferably carried out with a sufficiently large length, so that different angles of these respective line detectors 6a (

₁ , ...,

_n , ...,

Each of the line detectors 6a can be scanned across the entire object such that each line detector 6a can obtain a two-dimensional image of radiation as it is transmitted to the object 5 at each angle of _N ).

2a to 2c schematically illustrate three different x-ray bundles b ₁ , b _n and b _N when traversing the inspection object 5 when scanning by the apparatus of FIG. 1. Reference numeral 9 represents a plane parallel to the x-axis, which coincides with the scanning direction 8 and the front of the radiation detector 6.

₁에서 대상물에 투과된 방사선의 이차원 이미지의 형성을 예시하고, 도 2b는 각도

_n이지만, 동일한 대상물에 투과된 방사선의 이차원 이미지의 형성을 예시하며, 도 2c는 각도

_N이지만, 유사한 이차원 이미지의 형성을 예시한다.As can be seen in FIGS. 2A-2C, each line detector / X-ray bundle pair produces a complete two-dimensional image at different angles. 2A is an angle

Illustrates the formation of a two-dimensional image of radiation transmitted to an object at ₁ , FIG. 2B being an angle

_n but illustrates the formation of a two-dimensional image of radiation transmitted through the same object, FIG. 2C being an angle

_N, but illustrates the formation of similar two-dimensional images.

_N-

₁ 에 걸쳐 분포된다. 일군의 라인 검출기들에 있는 라인 검출기(6a)들의 개수는 상이한 각도에서 기록된 이미지들의 개수(검사 시에 요구됨)에 따라 적어도 3개, 바람직하게는 적어도 10개, 가장 바람직하게는 적어도 25개이다.Preferably, the different angles range from an angle of at least 5 °, preferably at least 10 °, most preferably at least 15 °, depending on the application or type of test to obtain high quality toxin syndase data for object inspection.

_N-

Distributed over ₁ The number of line detectors 6a in the group of line detectors is at least 3, preferably at least 10, most preferably at least 25, depending on the number of images recorded at different angles (required at the time of inspection).

The scanning steps of FIGS. 2A-2C indicated by sl depend on the spatial resolution of the two-dimensional image formed from the one-dimensional records. Typically, the scanning step sl can be approximately 10-500 microns and the individual detection elements of each line detector can be of similar size.

) 만큼 회전시킨다. 각도(

)는 바람직하게 상이한 각도(

₁, ...,

_n, ...,

_N 중 하나의 인접한 각도인 2개의 각도들 사이의 차보다 작다.Advantageously, a device 7, or other device (not shown) that performs a scanning motion, passes through the radiation source 1, the collimator 4 and the radiation detector 6, for example through the radiation source 1 or other points. And an angle about the rotation axis perpendicular to the axis of symmetry 3, preferably parallel to the y axis,

Rotate by) Angle(

) Is preferably a different angle (

₁ , ...,

_n , ...,

_Is less than the difference between two angles, which is an adjacent angle of one of _N.

However, the radiation source 1 can still be maintained during rotation if the line detector 6a remains within the solid angle of the radiation emitted by the radiation source 1 after the rotation.

₁+

, ...,

_n+

, ...,

_N+

) 들 각각의 각도에서 대상물(5)에 투과된 방사선의 또 다른 다수의 라인 이미지들을 기록한다.The moving device 7 then repeats the linear movement of the radiation source 1, the collimator 4 and the radiation detector 6 in relation to the object 5 in a second scan, while each line The detector is another different angle (

₁ +

, ...,

_n +

, ...,

_N +

) Records another multiple line images of radiation transmitted to the object 5 at each angle.

In Figures 3A-3C, three different X-ray bundles b ₁ , b _n and b _N are used to cross the inspection object 5 during the second scanning movement by the apparatus of FIG. 1. Different X-ray bundles are schematically illustrated. Reference numeral 9 denotes a plane parallel to the x-axis, as in FIG. 2A, where this plane is slightly biased from the scanning direction 8 and from the front of the radiation detector 2 due to rotation.

₁+

)에서 대상물에 투과된 방사선의 이차원 이미지의 형성을 예시하고, 도 3b는 각도(

_n+

)이지만, 동일한 대상물에 투과된 방사선의 이차원 이미지의 형성을 예시하며, 도 3c는 각도(

_N+

)이지만, 유사한 이차원 이미지의 형성을 예시한다.As can be seen in FIGS. 3A-3C, each line detector / X-ray bundle pair produces a complete two-dimensional image at different angles. 3a is an angle (

₁ +

Illustrates the formation of a two-dimensional image of radiation transmitted to an object in FIG.

_n +

), But illustrates the formation of a two-dimensional image of radiation transmitted through the same object, and FIG. 3C shows an angle (

_N +

, But illustrates the formation of similar two-dimensional images.

₁,

₁+

, ...,

_n,

_n+

, ...,

_N,

_N+

)에서 2N의 이차원 이미지의 형성에 대비된 것이다. 유사하게, 회전 및 선형 스캐닝은 P회 반복되어 P×N의 이차원 이미지를 얻을 수 있다. 이러한 방식으로, 상이한 각도들에서의 다수의 이미지들은 한정된 개수의 라인 검출기를 사용함으로써 얻어질 수 있다. 이 결과, 저가의 방사선 검출기가 연장된 스캐닝 및 검사 시간을 희생하여 제공될 수 있다. 그러 나, 검사 중 대상물(5)에 대한 총 방사선량은 증가될 필요가 없다.Therefore, two linear scans with a slight rotation between themselves are different angles (

₁ ,

₁ +

, ...,

_n ,

_n +

, ...,

_N ,

_N +

In contrast to the formation of 2N two-dimensional images. Similarly, rotational and linear scanning can be repeated P times to obtain a two-dimensional image of P × N. In this way, multiple images at different angles can be obtained by using a finite number of line detectors. As a result, low cost radiation detectors can be provided at the expense of extended scanning and inspection time. However, the total radiation dose to the object 5 during the test need not be increased.

Alternatively, or in addition, the rotation may be performed about a rotation axis center parallel to the x axis between linear scans of the kind described above.

The more images provided at different angles, the smaller the noise resulting from overlapping objects in the reconstructed tomosinic size.

It should be noted that the present invention can be applied to any type of examination using tomosincisize or laminographic imaging techniques, including for example mammography and other soft tissue examinations.

Preferred line detectors for use in the present invention are gas-based parallel plate detectors preferably equipped with electronic avalanche amplifiers. Such a gas-based parallel plate detector is an ionization detector, wherein electrons released as a result of ionization by ionization of the radiation are accelerated in a direction perpendicular to the direction of the radiation.

A cross section of the line detector of FIG. 1 taken along line I-I of FIG. 1 is schematically illustrated in FIG. 4.

The line detector comprises a window 27 for the incidence of the light bundle and a strip 27 which is arranged on the dielectric substrate 28 and extended in a row of respective conductive detector elements. Preferably, the anode of the line detector is adapted to attract strips 27, each of which is a conductive detector element capable of individually detecting incident radiation photons, and also to attract electrons released during ionization of the ionizable gas in the line detector. It can also be Preferably, dielectric substrate 28 and window 30 define an airtight compartment, which may be filled with an ionizable gas, with sidewalls 29, 31, 32 and a dielectric cathode substrate, not shown. Optionally, the line detector is arranged in an external hermetic case (not shown).

The individual conductive detector / anode elements 27 are arranged side by side in a state parallel to the y direction to define respective angles β ₁ , ..., β _m , ..., β _M with respect to the xz plane. It should be noted that all detector / anode elements 27 are directed towards the X-ray source 1, thereby avoiding any parallax error caused by divergent radiation. As a result, different detector / anode elements 27 detect different angular portions β ₁ ,..., Β _m , ..., β _M of the light bundles incident into the line detector.

For a more detailed description of this kind of gas based line detectors for use in the present invention, reference is made to the following U.S. patents filed by Tom Frank et al. And assigned to XCounter AB, Sweden, which patents , Patent No. 6,546,070; 6,522,722; 6,518,578; 6,118,125; 6,373,065; 6,337,482; 6,385,282; 6,414,317; 6,476,397; And 6,477,223, which are incorporated herein by reference.

In particular, it should be noted that this kind of detector is very effective in preventing the detection of Compton scattered radiation. This property is of paramount importance in obtaining high quality tomosindisize data.

The distance between the parallel plates, ie between the electrodes of the line detector, is between about 2 mm or less, preferably about 1 mm or less, more preferably about 0.5 mm or less, most preferably between about 0.1 mm and 0.5 mm Can be. XCounter AB has recently begun experimentally demonstrating the elastic scattering rejection characteristics of line detectors, and good contrast is observed using the wide X-ray spectra of high energy X-rays. No structure could be seen at all. It is contemplated that the gas-based line detector described above identifies more than 99% of the scattered photons, and by appropriate design, it can be prevented that approximately 99.9% or more of the scattered photons are detected.

Nevertheless, it will be appreciated that any other type of detector may be used in the present invention. These line detectors have incidence on the edge of scintillator based arrays, CCD arrays, TFT and CMOS based detectors, liquid detectors and X-rays, near or perpendicular incidence on the edges and, if necessary, X-rays Solid-state detectors, such as one-dimensional pin-diode arrays, which may have a collimator structure in front to partially reject them.

The device 7 for firmly connecting the X-ray source 1, the collimator 4 and the radiation detector 6 is a separate unit for the X-ray source 1, the collimator 4 and the radiation detector 6. It should also be noted that the devices may be replaced with devices (not shown), which devices may be electrically controlled to obtain a similar scanning motion by obtaining the simultaneous motion of the separate devices. In addition, the apparatus of FIG. 1 can be modified such that the object 5 is moved during scanning while the radiation source 1, the collimator 4 and the radiation detector 6 remain at rest.

It should also be noted that instead of performing a linear scan during each rotation, linear scanning may be performed in stages, and in each of these linear scanning steps, measurements may be made during different rotations. The results are the same, but the measurements are performed in a different order.

) 만큼 회전된다. 제 2 스캐닝 중, 복수의 라인 검출기들의 스트립들은 β₁+

, ..., β_m+

, ..., β_M+

을 갖고서 xz 평면에 경사지게 된다. 그러므로, 자체들 사이에서 약간의 회전을 갖는 2개의 선형 스캔은 상이한 각도들(β₁, β₁+

, ..., β_m, β_m+

, ..., β_M, β_M+

)에서 2M의 이차원 이미지의 형성을 제공한다. 유사하게, 회전 및 선형 스캐닝은 P회 반복되어 P×M의 이차원 이미지를 얻을 수 있게 한다.It should also be noted that in another embodiment of the present invention, linear scanning is performed in the y direction, and rotation between linear scannings is performed about an axis parallel to the x axis. This requires a very short distance between line detectors in a group state, since one detector strip from each line detector provides an instant one-dimensional image. One complete scan in the y direction involves the movement of each detector strip of each line detector across a complete object. Strips of a plurality of line detectors inclined in the xz plane with an angle β ₁ record one-dimensional images during scanning, and adjacent strips record different two-dimensional images at different angles. After the first scan, the detector has an angle (+

Rotate by) During the second scanning, the strips of the plurality of line detectors are β ₁ +

, ..., β _m +

, ..., β _M +

Inclined to the xz plane. Therefore, two linear scans with a slight rotation between themselves have different angles β ₁ , β ₁ +

, ..., β _m , β _m +

, ..., β _M , β _M +

) Provides the formation of a two-dimensional image of 2M. Similarly, rotational and linear scanning can be repeated P times to obtain a two-dimensional image of P × M.

Claims (18)

A scanning-based device for obtaining tomosinic size data of an object (5), A diverging radiation source 1 provided for emitting radiation 2 concentrated around an axis of symmetry 3; Each of which is directed towards the divergent radiation source,

₁ , ...,

_n , ...,

_N ) includes a group of line detectors 6a for causing the ray bundles of radiation b ₁ ,..., B _n ,..., B _N to propagate at line angles to the line detectors. A radiation detector 6; An object region arranged in a radiation path between the divergent radiation source and the radiation detector for receiving the object; And The divergent radiation source and the radiation related to the object while the respective line detector is adapted to record a plurality of line images of radiation transmitted to the object at each angle of the plurality of different angles. And a device (7) provided for linearly moving a detector in a direction (8) perpendicular to the axis of symmetry. The method of claim 1, The radiation detector 6 is angled about an axis of rotation perpendicular to the axis of symmetry 3

And a device provided for rotating by the line detector, wherein the line detector 6a is each oriented towards the divergent radiation source after the rotation, so that another plurality of different angles (

₁ +

, ...,

_n +

, ...,

_N +

Causing the light bundle of radiation to propagate at each angle of the beams to the line detector, The device 7 provided for moving is further arranged to repeat linear movement of the diverging radiation source and the radiation detector in relation to the object, while each of the line detectors is arranged in the another plurality of different angles (

₁ +

, ...,

_n +

, ...,

_N +

Scanning-based device, adapted to record another plurality of line images of radiation transmitted to the object at each angle of the plurality of beams. The method of claim 2, The axis of rotation passes through the divergent radiation source (1). The method of claim 2 or 3, The rotating device is adapted to repeatedly rotate the radiation detector 6 about the axis of rotation such that the line detectors 6a are directed towards the divergent radiation source after each of the rotations, respectively. A ray bundle of radiation propagating at each angle is incident on a line detector, The device 7 provided for moving is adapted to repeat the linear movement of the diverging radiation source and the radiation detector associated with the object after each said rotation, while each of said line detectors are each Scanning-based device adapted to record a line image of radiation transmitted to the object at an angle of. The method according to any one of claims 2 to 4, The line detector is directed to detect a line image perpendicular to the axis of symmetry 3 and extending in a direction y perpendicular to the direction 8, wherein the moving device 7 relates to the object. And a radiation detector provided to move the divergent radiation source and the radiation detector. The method of claim 5, And the direction (y) in which the line image extends is parallel to the axis of rotation. The method according to any one of claims 2 to 4, The line detectors are oriented to detect a line image perpendicular to the axis of symmetry 3 and extending in a direction y parallel to the direction y, wherein the moving device 7 is in contact with the object. Provide for moving the divergent radiation source and the radiation detector in relation; And the direction (y) in which the line image extends is perpendicular to the axis of rotation (x). The method according to any one of claims 1 to 7, The plurality of different angles may be in the range of angles of at least 5 °, preferably at least 10 °, most preferably at least 15 ° (

_N to

Scanning based device characterized in that distributed over ₁ ). The method according to any one of claims 1 to 8, The number of line detectors (6a) in said group of line detectors is at least three, preferably at least ten and most preferably at least 25. The method according to any one of claims 1 to 9, The moving device 7 scans each of the line detectors across the entire object such that the respective line detectors obtain a two-dimensional image of radiation transmitted to the object at each angle of the plurality of different angles. Scanning-based device adapted to move the divergent radiation source and the radiation detector in relation to the object by a length sufficient to be below. The method according to any one of claims 1 to 10, The divergent radiation source is an X-ray source (1); And, The line detectors are each gas based ionization detectors 6a, Scanning-based device, characterized in that the freed electrons as a result of ionization by each ray bundle are accelerated in a direction perpendicular to the direction of the ray bundle. The method of claim 11, The gas based ionization detector is an electron avalanche detector (6a). The method according to any one of claims 1 to 12, And the line detector is one of a diode array, a scintillator based array, a CCD array, a TFT or CMOS based detector, or a liquid detector (6a), respectively. The method according to any one of claims 1 to 13, A collimator (4) arranged in a radiation path between said radiation source and said object region, And the collimator prevents radiation that is not directed towards the line detector from impinging on the object, thereby reducing the radiation dose to the object. A diverging radiation source 1 which emits radiation 2 concentrated around an axis of symmetry 3; And Each is oriented towards the divergent radiation source, thereby providing a plurality of different angles (

₁ , ...,

_n , ...,

_N The radiation of the ray bundle to propagate in each angle _{of) (b 1, ..., b} n, ..., b N) of radiation containing the line detectors (6a) of the group to be is incident on the detector line As a scanning-based method of using the detector 6 to obtain toxin synthesized data of the object 5, Arranging the object in a radiation path between the divergent radiation source and the radiation detector; And The angle of each of the plurality of different angles is moved by each of the line detectors while simultaneously moving the divergent radiation source and the radiation detector associated with the object in a direction 8 perpendicular to the axis of symmetry. And recording a plurality of line images of the radiation transmitted to the object. The method of claim 15, The radiation detector 6 is angled about an axis of rotation perpendicular to the axis of symmetry 3

), The line detectors 6a are each oriented towards the divergent radiation source after the rotation, so that another plurality of different angles (

₁ +

, ...,

_n +

, ...,

_N +

Causing the light bundle of radiation propagating at each angle of the beams to be incident on the line detector; And Each of said line detectors to said another plurality of different angles (

₁ +

, ...,

_n +

, ...,

_N +

Repeating linear movements of the diverging radiation source and the radiation detector in relation to the object while being adapted to record another plurality of line images of radiation transmitted to the object at each angle of Scanning based method further comprising. The method of claim 16, The axis of rotation passes through the divergent radiation source (1). The method according to claim 16 or 17, The moving may include scanning each of the line detectors across the entire object such that each line detector obtains a two-dimensional image of radiation transmitted to the object at each angle of the plurality of different angles. Moving the divergent radiation source and the radiation detector associated with the object by a sufficient length.

Images